This invention relates to a thermally gellable artificial latex composition useful for preparing an article such as a glove, a condom, or a balloon.
In view of the alarming increase in the incidence of contagious diseases, there has been an increasing need for protective materials, such as gloves and condoms. These protective materials are commonly made from a natural rubber latex or polyvinylchloride (PVC). Natural rubber latex gloves are preferred because they are more comfortable than PVC, but suffer from some serious disadvantages. First, the rubber vulcanization chemicals used in the manufacturing process are known to cause severe skin sensitization. Second, proteins present in natural rubber can cause an immunoglobulin E mediated allergic reaction in sensitized individuals, leading to anaphylaxis. It would therefore be desirable to find an alternative protective material that has equivalent performance as natural rubber without the disadvantages.
Preformed polymers colloidally dispersed in an aqueous medium (artificial latexes) are known and are chiefly used in the fields of coatings and additives. Artificial latexes can be prepared in the absence of vulcanizing agents and proteins by the steps of: 1) providing a solution of a copolymer in a volatile organic solvent; 2) emulsifying the solution with water and an aqueous emulsifier; and 3) removing the volatile organic solvent from the emulsion; and 4) adjusting the solids content if desired. Preparations of copolymers are described in U.S. Pat. Nos. 3,135,716 3,150,209, 3,496,154, 3,498,960, 4,145,298, and 4,169,115. Preparations of artificial latexes are described in U.S. Pat. Nos. 3,360,599, 3,503,917, 4,123,403, and U.S. Pat. No. 5,037,864, all incorporated herein by reference.
There remains a need for artificial latex compositions suitable for preparing articles that have the high tensile strength and the high elongation at break of natural rubber, without the drawbacks.